Patent Literature 1: JP 2006-088912 A (US 2006/0069483 A1)
Patent Literature 1 discloses a vehicle-occupant protection system which is mounted in a vehicle to protect an occupant of the vehicle from a vehicle collision. The vehicle-occupant protection system includes, for example, an airbag and a pretensioner. The airbag deploys upon a vehicle collision to protect the occupant. The pretensioner binds (holds) the occupant for protection purposes before the occupant moves forward during the vehicle collision.
A conventional vehicle-occupant protection system includes a sensor and a collision determination section. The sensor detects a vehicle collision. In accordance with a detection signal from the sensor, the collision determination section determines whether a vehicle collision has occurred. When the collision determination section concludes that a vehicle collision has occurred, it activates protection means such as the airbag and the pretensioner.
In recent years, it is demanded that the vehicle-occupant protection system be applicable not only to a front-rear collision and a lateral collision, but also to a front oblique collision (oblique collision). In an oblique collision, a collision target collides against the vehicle in an oblique direction of the vehicle (in a direction from a front-oblique point to the vehicle). If, for example, an oblique collision occurs against a front door of the vehicle, the occupant relatively moves toward the collision target (collision spot) due to inertia. Such an occupant movement decreases the clearance between the collision target (collision spot) and the occupant. This might increase the value of damage received by the occupant. When the above-described oblique collision occurs, it is beneficial to suppress an increase in the value of damage received by the occupant by activating the pretensioner to provide an adequate clearance between the collision target and the occupant.
However, the conventional vehicle-occupant protection system provides occupant protection during an oblique collision under the same conditions as for a lateral collision. In other words, the oblique collision is handled in the same way as the lateral collision. In this instance, it is probable that the occupant may be inadequately protected during the oblique collision. Particularly, an increase in the value of damage caused by the movement of the occupant may not be sufficiently suppressed.